I just installed iOS 9 GM on my iPhone. Before I installed it my phone was seeing the WatchOS 2 GM update. However, I thought it would be better to install the iOS 9 GM before updating the watch so I did the iOS 9 GM update first. I made sure the latest WatchOS 2 GM beta profile build 3S343 was installed on both the watch and iPhone. However, it keeps saying "Checking for Updates..." then it says "Unable to Check for Updates. Checking for a software update failed because you are not connected to the Internet." I tried resetting the network settings, resetting the watch, etc. I even tried removing the beta profiles but then it just says there is no software update available. My WatchOS is on build 13S5325c which is the latest beta build. Since my phone saw the GM build of the watchOS when I still had iOS 9 beta I'm guessing only the beta of iOS 9 will update to watchOS 2 GM but not the iOS 9 GM. Has anyone else ran into this?
WatchOS 2 GM stuck on checking for updates
Nevermind... I guess it had something to do with my WiFi since the update is showing up when connected to LTE. Oops. 😊
Try resetting your router.
EDIT: Oh, it seems you've already come to a similar conclusion 🙂
Tried it with and without WiFi - no luck.
iPhone 6+ with iOS9.0, Apple Watch running watch OS beta.